Safe Tire Pressure

[slowmover]

Why I deleted it. The consistency among trailer manufacturers, trailer tire manufacturers, and from our tire engineers is good enough for me. Having torn tires off of trailers (18-wheelers) it was a concern of mine from the beginning with our last SS. I'll let you all keep on.

Your truck, mine, others isn't being pushed/pulled by a long pole. That's what makes the difference.

.

[dznf0g]

Originally Posted by REDNAX

Why I deleted it. The consistency among trailer manufacturers, trailer tire manufacturers, and from our tire engineers is good enough for me. Having torn tires off of trailers (18-wheelers) it was a concern of mine from the beginning with our last SS. I'll let you all keep on.

Your truck, mine, others isn't being pushed/pulled by a long pole. That's what makes the difference.

.

Not sure who you are addressing...or what you mean. Could you detail?

[slowmover]

Tired from work. Deleted because it was leading nowhere.

Tire damage is cumulative in this instance (TT's) when pressures are not what they should be. I'll leave defining "should be" to the tire & trailer manufacturers (and the outside professionals who've commented) as good enough for me, for now.

Getting the right Load Index seems to be the problem of LT: High enough on one hand, but not too high (rough ride) on the other. I see maximum tire pressure as a given for any tire chosen, not as an option in this.

Others have different takes.

.

[slowmover]

Tireman9 on tandem axle tire distortion

[dznf0g]

Originally Posted by REDNAX

Tireman9 on tandem axle tire distortion

Hmm, a convincing argument for running 80psi for my 30'er. Sorta correlates with my temp rise findings as well.

[slowmover]

Trailer Tire Facts - Discount Tire

Note the use of "20%" in the above. Correlates with the ideal of 15% load reserve per tire, but takes it to the vehicle whole rather than wheel-by-wheel.

As always, the problem is the word, "safe". Reducing risk, yes, eliminating it, probably not. But how far can we reduce it (the problem all of us are set to try to solve). Knowing we've gotten to 80%+ would be good. 90%, great. We already know we can't make that last 10% (all in a manner of speaking).

As a result of all this tire stuff I finally got myself a 120V 1HP/3-GL air compressor. Craftsman. Correct shape for my storage space available and any heavier would be too heavy. Just need to decide on a sub-$100 calibrated 0-100 psi tire pressure gauge next. Now I can make changes easily and accurately.

One comment I came across today (an old thread hereabouts, IIRC) is that there is a final two-pounds where (for the TV) the pressure rise takes off (a concern of racers). I'll stick with five pound increments FWIW.

.

[Ag&Au]

Originally Posted by REDNAX

Trailer Tire Facts - Discount Tire

.................................................. ......

.

If we are to accept everything written in that reference, then we all better be using ST tires.

From that reference:
Why Use An "ST" Tire

• "ST" tires feature materials and construction to meet the higher load requirements and demands of trailering.
• The polyester cords are bigger than they would be for a comparable "P" or "LT" tire.
• The steel cords have a larger diameter and greater tensile strength to meet the additional load requirements.
• "ST" tire rubber compounds contain more chemicals to resist weather and ozone cracking.

This whole subject is beginning to take on more of the attributes of religions, than it is of science.

Ken

[dznf0g]

Originally Posted by w7ts

If we are to accept everything written in that reference, then we all better be using ST tires.

From that reference:
Why Use An "ST" Tire

• "ST" tires feature materials and construction to meet the higher load requirements and demands of trailering.
• The polyester cords are bigger than they would be for a comparable "P" or "LT" tire.
• The steel cords have a larger diameter and greater tensile strength to meet the additional load requirements.
• "ST" tire rubber compounds contain more chemicals to resist weather and ozone cracking.

This whole subject is beginning to take on more of the attributes of religions, than it is of science.

Ken

Not religion for me, I am looking to physics and actual numbers (loads vs. pressure rise, etc.)

[slowmover]

This whole subject is beginning to take on more of the attributes of religions, than it is of science.

Digging for details ain't theology. If there is consistency about tires (weight ratings, pressure recommendations, etc) then questions about which tire is "best" changes nothing on how to use it. Two separate questions.

.

[Ag&Au]

Originally Posted by REDNAX

This whole subject is beginning to take on more of the attributes of religions, than it is of science.

Digging for details ain't theology. If there is consistency about tires (weight ratings, pressure recommendations, etc) then questions about which tire is "best" changes nothing on how to use it. Two separate questions.

.

I wasn't directing that at you, though I see that it looked like it. I am talking about those that when confronted with documentation and opinions from experts, still choose to disregard all that and stick with their original beliefs.

The proper approach is, as you say, to search for facts to base an independent conclusion on. Unfortunately, that is being thwarted by our litigation happy society. It has made all those that have the in depth knowledge necessary to arrive at a common sense solution paranoid to share it. They are quite justified in believing some fool will do something entirely stupid and then sue them because they didn't publish enough "Warnings to Morons" on the product.

Ken

[dznf0g]

Ah, I get 'cha now, Ken.

[Ag&Au]

Originally Posted by dznf0g

Ah, I get 'cha now, Ken.

Thanks for understanding what I was trying to say.

I firmly agree that getting the numbers and then understanding how to use them is the key to most physical problems including what tire to use and how to use it.

The difficulty here is separating what the experts and manufacturers are telling us because it is a proven fact from what they are telling us because they are afraid of liability or what they are telling us because of the profit margins.

I'm thinking November may turn out to be my personal month of cynicism.

Ken

[slowmover]

And I didn't take it personally. Maybe if I was Bibeau in an alternate universe . . . .

And profits + litigation-fear hampers free speech. That is the result of a society dominated not by government [us], but by corporations. It is up to us to report to NHTSA tire failures that a record can be made (details provided by both tire engineers on how and where [insight] to making such).

The pursuit is worth the trouble in this, the subject of this thread.

.

[rodsterinfl]

Wow. Ok, for those that still have the trailer tires; I have Tomax 15" D Rated tires that have a 65psi maximum cold pressure on the side of the tire. According to Mojo, I am to inflate them to 65psi. Sounds logical. I decided to go to 60psi. I want to make sure that I do not over inflate them because of temperature. Also, with vehicles I have always used the vehicle sticker which is always lower than the maximum on the tire. Does Airstream have a psi/tire sticker that I am missing?

[CapriRacer]

Originally Posted by rodsterinfl

Wow. Ok, for those that still have the trailer tires; I have Tomax 15" D Rated tires that have a 65psi maximum cold pressure on the side of the tire. According to Mojo, I am to inflate them to 65psi. Sounds logical. I decided to go to 60psi. I want to make sure that I do not over inflate them because of temperature........

Tires are designed to be able to withstand the pressure buildup due to operating temperature - and then some. You should have used the 65 psi.

If you are worried about the difference in pressure due to the change in ambient temperature - again, there is plenty of reserve that you really don't have to worry about it - especially considering that under-inflation is much, much more of a concern.

[switz]

The California AS dealer (service manager with over 30 years AS experience) suggested 60 psi in the Fall (CA and AZ) and run 55 psi in the summer in AZ. These numbers are for stock GYM tires on a Int'l 25FB that has sticker GVW of 7,300 pounds.

Reading this article has left a new owner confused. I did see new 16" wheels and appropriate Michelin tires at JC this fall and they would gladly retrofit those 16" tires and wheels for several thousand dollars. They also have a disk brake conversion that is very expensive. Going the16" route raises the height of the trailer thus impacting how my Hensley Arrow would interface to my TV.

Thanks for the discussion.

[slowmover]

Originally Posted by switz

The California AS dealer (service manager with over 30 years AS experience) suggested 60 psi in the Fall (CA and AZ) and run 55 psi in the summer in AZ. These numbers are for stock GYM tires on a Int'l 25FB that has sticker GVW of 7,300 pounds.

Reading this article has left a new owner confused. I did see new 16" wheels and appropriate Michelin tires at JC this fall and they would gladly retrofit those 16" tires and wheels for several thousand dollars. They also have a disk brake conversion that is very expensive. Going the16" route raises the height of the trailer thus impacting how my Hensley Arrow would interface to my TV.

Thanks for the discussion.

Leave the confusion aside a moment. If the TT were equipped state-of-the-art (antilock disc brakes plus "better" tires/wheels) and the TV had the best hitch . . . what would be the percentage cost increase to the pair of vehicles at the outset? I find this avenue more productive for investigatory reading. That the factory long ago quit being a leader in TT performance is a take-away from that point-of-view. Were these production line standard then the cost would be moot.

The tires have to translate all of the above. The less they are called upon to perform to their outmost limits is crucial. The above addresses this.

Where the rubber truly meets the road.

FWIW, I've had to exchange my H/A stinger twice. About to do it again (different hitch receiver height, and other differences). Proper re-adjustment isn't onerous.

Good luck

.

[BlackAces]

Originally Posted by Morgan guy

I have a 2007 AS Classic 27'. It has a GVWR of 9000 lbs. I havve 4 Maxxis load range E tires rated at a capacity of 2830 lbs/ 80 Psi, for a total load of 11,320 lbs. With an excess capacity of 2,320 lbs, I would like to run a lower air pressure than 80 lbs to give a softer ride to the trailer. Does anyone know how the pressure adjustment affects the load capacity, in other words, what can I safely lower the pressure. The label on the trailer says 65 lbs but doesn't reference what load range of tire.

When increasing load capacity with ST tires, it’s normally to prevent early tire failures, which the extra load capacity helps insure against.

Maxxis supports the vehicle manufacturers recommended tire pressures 100%. Had you used LT tires for your upgrade you could have used the industry standards and set a new recommended tire pressure. However, Maxxis will only support the pressures for your (ST) LRE tires that are recommended by the vehicle manufacturer. So, until you talk with someone at Airstream authorized to set new tire pressures for your upgrade you should air them to 80 psi. Maxxis will not honor the warranty without documentation.

I had a long talk with the Maxxis East Coast representative about this very subject not long ago. His name is Shawn Brennan and his business phone number is 687-407-6772.


BlackAces

[richcrest]

My 19' Safari Bambi takes ST225/75 R15 D-range tires with a 65 psi max inflation. I have noticed that the center of the tread wears out before the edges, creating a visible depression in as little as 3K miles. Would it be worth it to run the Marathons at 60 psi instead of 65?

[Inland RV Center, In]

Originally Posted by richcrest

My 19' Safari Bambi takes ST225/75 R15 D-range tires with a 65 psi max inflation. I have noticed that the center of the tread wears out before the edges, creating a visible depression in as little as 3K miles. Would it be worth it to run the Marathons at 60 psi instead of 65?

The tire maximum rating, is exactly that.

That pressure should be used when you have loaded the tires to the maximum, and not "just because".

Normally, for a moderate load with load range "D" tires, a pressure of 50 to 55 PSI, will get the job done, and the tires will wear evenly, assuming that the running gear has been properly balanced.

Andy